Mohamed El-Baradei, the head of the International Atomic Energy Agency, or IAEA, traveled to North Korea on March 13 to discuss sending nuclear inspectors back into the country.

North Korea expelled IAEA inspectors in December 2002. And now, more than four years later, they are on the verge of going back in. The return of IAEA inspectors is an important element of the February 13 agreement reached by the six-party talks discussing North Korea's nuclear weapons program.

The agreement calls on Pyongyang to freeze plutonium production and reprocessing at its Yongbyon plant within 60 days of the accord and to allow IAEA inspectors to monitor and verify the freeze. In exchange, North Korea would get 50-thousand tons of heavy fuel oil.

David Kay, former IAEA chief nuclear weapons inspector, says El-Baradei will have to negotiate exactly what the inspectors' responsibilities will be in North Korea. "Mohamed El-Baradei, on behalf of the International Atomic Energy Agency, has to judge whether what the North Koreans are willing to accept meets the requirements of effective nuclear safeguards. I suspect that's going to be the start of some really tough negotiations, with the IAEA pressing for intrusive inspections that would give it confidence as to whether North Korea is continuing with its plutonium production and separation - - and whether the North Koreans are willing to accept that," says Kay. 

North Korea's Nuclear Infrastructure

Experts say there are two ways to make fissile material for nuclear weapons. One way is to produce plutonium and the other is through the process of enriching uranium.

David Albright, President of the Institute for Science and International Security - - a private organization that tracks nuclear weapons - - says there is a fair amount of information about North Korea's Yongbyon plutonium plant. "There's a reactor - - it's a relatively small one, it's called a five megawatt electric reactor. There's an associated plant to take the irradiated fuel from the reactor and separate the plutonium - - and that's called a radio chemical laboratory. There is a fuel fabrication complex and there is also a much bigger reactor - - a 50 megawatt electric reactor - - under construction at Yongbyon. And so all those facilities and all the further construction of the 50-megawatt electric reactor comes to a halt. And there isn't any evidence that North Korea has any other plutonium production facilities," says Albright. 

While there is substantial information on North Korea's plutonium production complex, experts say little is known about Pyongyang's uranium enrichment program - - and there are even questions as to whether it ever existed. What is known is that North Korea received technology from Pakistan for such a program.

In his memoirs, Pakistani leader Pervez Musharraf says A.Q. Khan - - the father of Pakistan's nuclear bomb - - transferred to North Korea nearly two dozen centrifuges - essential components of a uranium enrichment program - - as well as coaching on centrifuge technology.

Denials and Tense Relations

In October 2002, the Bush administration confronted North Korea with that information. According to U.S. officials, Pyongyang first admitted, then denied it was pursuing a uranium enrichment program. Publicly, North Korea has rejected accusations it was engaged in such an endeavor.

A CIA report at the time made it clear that intelligence officials believed North Korea was - - in the words of the report - - "constructing a plant that could produce enough weapons grade uranium for two or more nuclear weapons per year when fully operational - - which could be as soon as mid-decade."

David Albright felt that the information at the time was flawed. "In 2002, when the U.S. intelligence community first made this assessment public, I think it was hyped up. And I believe personally that what we heard about in public represented a flawed assessment based on extrapolations from a relatively small set of information. And these statements were made to Congress, they were made to the press and were used at the time to basically discredit the 'Agreed Framework' that had been established under the Clinton administration with North Korea and to disrupt cooperative initiatives that were ongoing or growing between North Korea and its neighbors. So I think this flawed assessment did a lot of damage," says Albright. 

Albright and others say relations between Pyongyang and Washington worsened. Talks between the two parties ended. Fuel shipments to North Korea stopped. Retaliating, North Korea expelled IAEA inspectors, left the nuclear non-proliferation treaty, and resumed plutonium production, which ultimately led to last October's explosion of a nuclear device.

Just a few days ago [2/27/07], Joseph DeTrani, a U.S. intelligence expert on North Korea, addressed a congressional panel and softened the U.S. government's position on Pyongyang's supposed uranium enrichment program. "The assessment was with 'high confidence' that indeed they were making acquisitions necessary for - if you will - a production-scale program. And we still have confidence the program is in existence - at the 'mid confidence level', yes sir," DeTrani said.  

For Arnold Kanter, former U.S. Undersecretary of State from 1991 to 1993, the truth will come out soon enough. "This should all be clarified, at least to some extent, in the next phase of the negotiations when the North Koreans are obliged to make a full and complete declaration of all of their nuclear activities. Presumably, they would have to have something to say about whether they did acquire components that could be used for uranium enrichment and if so, what's become of them?"

In the meantime, experts expect tough bargaining ahead as the United States and others try to persuade North Korea to give up its nuclear weapons for good.

This story was first broadcast on the English news program, VOA News Now. For other Focus reports click here.